In a wireless telecommunications network, subscriber access units provide a wireless communication link between user PCs and a base station processor connected to a public access network. Each of the base station processors serves a wireless coverage area, or sector, defined by the physical transmission capacity of the base station processor which serves the sector. In order to provide uninterrupted service to a mobile subscriber access unit, the sectors typically have overlapping portions. As a result of the overlapping portions, a subscriber access unit may concurrently be within multiple sectors each served by a base station processor.
A subscriber access unit maintains a wireless communication link to the base station processor via a wireless session context. The session context corresponds to a plurality of connections used to provide message traffic to and from the user PCs. When a subscriber access unit is within multiple sectors, it may establish a wireless session context via the base station processor serving any of the multiple sectors. In this manner, a subscriber access unit may be served from any of the candidate base station processors which serve the multiple sectors.
Each base station processor typically serves many subscriber access units. The number of subscriber access units served by a base station processor affects the throughput of each subscriber access unit in wireless communication with the base station processor. A loading factor is indicative of a traffic load on a base station processor, and therefore corresponds to the throughput which can be provided to each subscriber access unit. A high loading factor is indicative of a base station processor burdened with message traffic for many subscriber access units. Conversely, a low loading factor is indicative of an unburdened base station processor.
In a base station processor, it is computationally expensive to determine if a subscriber access unit is located in a portion of a sector which overlaps with another sector. It is further computationally expensive to determine if the loading factor corresponding to the base station processor serving the overlapping sector is less than that of the base station processor currently serving the subscriber access unit. Such determinations utilize resources that could otherwise be used for traffic through the base station processor. Accordingly, it would be beneficial to provide a subscriber access unit with the ability to determine the loading factor of each of the candidate base station processors corresponding to the overlapping sectors, and to allow the subscriber access unit to effect a session context transfer, or handoff, to the base station processor with a lower loading factor.